A customer may wish to access a Voice over Internet Protocol service using an endpoint device. For example, the customer may wish to use an Internet Protocol (IP) phone to initiate a call. The customer may then register the IP phone at a call control element (e.g., a server) located in the service provider's network. After the registration of the IP phone is completed, the IP phone may receive messages from any computer on the same Local Area Network (LAN). However, this capability creates a security risk for the VoIP customer. For example, an attacker may send a message for redirecting the voice packets to another device. The VoIP customer may be unaware that his/her conversations have been compromised.